(1) Field of the Invention
The present invention relates to a specimen heating device for use with an electron microscope, and more particularly to a specimen heating device for use with an electron microscope which is suitable for observing a specimen in a high temperature state.
(2) Description of the Prior Art
Recently, it has been required to observe in a high temperature state a fine region or area of a specimen which is for example of the order of nanometers or less in diameter. In such an observation, it is very important to prevent the specimen from vibrating or drifting because the specimen drift adversely affects image resolving power directly.
According to one of known specimen heating devices, a sample is held by a specimen holding member heated by a heater. According to another known specimen heating device, a sample is held by a heater. A specimen heating device of the former type is disclosed in Japanese utility model application laid-open No. 173159/1983 and a specimen heating device of the latter type is disclosed in Japanese patent application laid-open No. 267/1976. The known specimen heating devices are advantageous in that the specimen is efficiently heated but disadvantageous in that the specimen is liable to vibrate or drift.
In general, a power supply for the heater is arranged independently of a main body of the electron microscope which is ordinarily called a column and hence electric conductors through which an electric power is supplied from the power supply to the heater are physically or mechanically unstable. As a result, the electric conductors are liable to be affected by air convection in the room in which the electron microscope is arranged and external vibration. That is, they are liable to be moved by the external factors. It has been found through experimental studies by the inventors that the specimen vibration or drift is attributed to the movement of the electric conductors.